Abstract

Resonant holographic interferometry (RHI) is a non-intrusive, laser-based diagnostic that has the potential to quantify species concentrations in both gas-phase and multi-phase (liquid and gas) environments. The technique exploits the rapid change in refractive index of a probed medium near absorption features. The change in refractive index is significant enough to change the effective pathlength or create a phase change in the light tuned to the absorption line. These phase changes can be resolved interferometrically during reconstruction. The interferogram’s contours can then be analyzed for species concentration levels. One significant feature of RHI is its ability to uniquely create interferograms using species specific phase changes. Phase changes resulting from optical aberrations, thermal or pressure instabilities, or background species are subtracted out from the interferogram during reconstruction.

© 1998 Optical Society of America